The hindered amines, such as the derivatives of 2,2,6,6-tetramethylpiperidine have long been known as very effective stabilizers against the deleterious effects of actinic light. Indeed, a number of such compounds enjoy considerable economic success as light stabilizers for a host of organic substrates.
Hydroxylamines are known as stabilizers for various polymeric systems either when used alone or in conjunction with phenolic antioxidants, organic phosphorus compounds, hindered amines or the like, as is taught in U.S. Pat. Nos. 4,590,231 and 4,782,105, and 4,876,300.
Hindered amines substituted by a hydroxyl group on the N-atom of the piperidine ring are also known and are found to be effective processing stabilizers as taught in U.S. Pat. Nos. 4,590,231; 4,668,721 and 4,691,015. The instant compounds have both a hindered amine moiety and a hydroxylamine moiety where the N-OH group is not part of a piperidine ring. Such compounds are novel and allow for much greater flexibility in molecular structures than do the hydroxylamines of the prior art.
This can be especially seen where the N-atom of the hindered amine is substituted by a hydrocarboxy group. Such groups are non-interacting and allow the hindered amine to be used in poly(vinyl chloride), PVC, and acid catalyzed thermoset acrylic coatings where hindered amines with high basicity sometimes cause problems.